Some of the largest creatures on Earth may hold a link to understanding the health of human skin.

Last week, the journal Scientific Reports released the results of a study showing that blue whales respond to UV radiation much like humans do: tanning themselves and turning certain genes “on and off” depending on the amount of radiation that’s hitting them.

As co-author Mark Birch-Machin told BBC News, “When blue whales go on their holidays to the Gulf of California they get a tan the same way we do.” That tan protects them from something called “sunburned DNA.”

Exposure to ultraviolet light—be it in people or whales—can damage not just skin, but DNA in mitochondria, the so-called “battery packs of cells.” And sunburned DNA can lead to skin damage, aging, and, in a worst-case scenario, skin cancer.

The study also examined how sperm and fin whales handle solar radiation.

And whereas blue whales tan over long ocean excursions, spending some time underwater and some time breaching, sperm whales, “can spend up to six hours at a time on the surface of the ocean, leading to far greater exposure to UV light,” says Birch-Machin.

How, exactly, do sperm whales cope with all this unwanted light? Much like we do, as it were.

“Their bodies activate what amount to repair genes,” explains National Geographic. “This process is similar to how human bodies produce antioxidants in response to free radicals, molecules that can cause a lot of genetic and cellular damage.”

Fin whales, finally, fared very well in terms of sun damage because of their high levels of melanin.

The study also looked at genes that help fight cell stress in humans, reports the Los Angeles Times.

Sperm whales showed the highest expression of these genes, which may act as a “second line of defense,” since boosting melanin production may not be enough to counteract the increased UV radiation at the ocean surface. In contrast, blue whales may not need to rely on these genes since they get so little sun, while the deep pigmentation in fin whales may provide enough protection.

But the study didn’t measure the difference between the damage that UV radiation inflicts in humans versus whales, “so it’s possible the damage in whales is a hundredfold less than what you’d see in any human being,” reports the Times.

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